The invention relates to an apparatus for charging an electrical energy store from a three-phase AC voltage source. The invention also relates to a method for charging an electrical energy store from a three-phase AC voltage source.
A known apparatus for the three-phase charging of a battery comprises a boost converter and a buck converter, which are provided to match voltage levels and are designed in each case as separate units. In addition, the known apparatus comprises a grid filter which is provided to suppress disturbing influences of the boost or buck converter on the three-phase AC voltage grid.
DE 195 235 76 A1 describes an AC voltage-DC voltage power supply unit and a method for converting an AC voltage into a DC voltage in high-voltage systems. The AC voltage-DC voltage power supply unit described in that document comprises a semiconductor switch which has a lower breakdown voltage on a low-voltage side of the flyback converter than a semiconductor switch on a high-voltage side. The lower breakdown voltage can be achieved by means of a shunt regulator which regulates a clamping voltage on the low-voltage switch side.